Network addresses with encoded DNS-level information

ABSTRACT

Systems and methods are described to enable a DNS service to encode information into a network address to be advertised by the DNS service. Information encoded by a DNS service may include, for example, an identifier of a content set to which the network address corresponds (e.g., a domain name) and validity information, such as a digital signature, that verifies the validity of the network address. On receiving a request to communicate with the network address, a destination device associated with the network address may decode the encoded information within the network address to assist in processing the request. In some instances, the encoded information may be used to identify malicious network transmissions, such as transmissions forming part of a network attack, potentially without reliance on other data, such as separate mappings or contents of the data transmission.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

Generally described, computing devices utilize a communication network,or a series of communication networks, to exchange data. Companies andorganizations operate computer networks that interconnect a number ofcomputing devices to support operations or provide services to thirdparties. The computing systems can be located in a single geographiclocation or located in multiple, distinct geographic locations (e.g.,interconnected via private or public communication networks).Specifically, data centers or data processing centers, herein generallyreferred to as “data centers,” may include a number of interconnectedcomputing systems to provide computing resources to users of the datacenter. The data centers may be private data centers operated on behalfof an organization or public data centers operated on behalf, or for thebenefit of, the general public.

Service providers or content creators (such as businesses, artists,media distribution services, etc.) can employ a series of interconnecteddata centers to deliver content (such as web sites, web content, orother digital data) to users or clients. These interconnected datacenters are sometimes referred to as “content delivery networks” (CDNs)or content delivery systems. Existing routing and addressingtechnologies can enable multiple data centers associated with a contentdelivery system to provide similar or identical content to clientcomputing devices. In some instances, each data center providing a setof content may be referred to as a point-of-presence (“POP”). A contentdelivery system can maintain POPs over a wide area (or worldwide) toenable the system to efficiently service requests from clients in avariety of locations.

To provide access to content, server computing devices are generallyassociated with network addresses, enabling requests for communicationwith the server computing devices to be routed across a network. Thesenetwork addresses are generally formed by a series of bits formattedaccording to a defined protocol, such as the Internet Protocol (IP)version four (IPv4) or version 6 (IPv6). Because network addresses maybe difficult for humans to recognize and remember, CDNs can utilizeresolution systems that function to resolve human-readable identifiersinto corresponding network addresses. One example of such a resolutionsystem is the Domain Name System (DNS), which functions to resolvedomain names into corresponding network addresses.

Generally, DNS services and CDNs operate independently and according todiffering protocols. For example, DNS requests from a client computingdevice are generally routed via the DNS protocol through multiple DNScomponents to a DNS service, where a network address corresponding to adomain name is returned via the DNS protocol. When a network address isobtained, the client computing device may then communicate with a servercomputing device associated with the network address (e.g., via thehypertext transport protocol, or “HTTP”). The respective processes ofDNS resolution and communication with a network address are thereforegenerally logically distinct, such that a server computing deviceobtaining a request for content at a network address is unaware of aprior DNS resolution (if any) that facilitated the request.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting an illustrative logical networkincluding multiple accessing computing devices 102 and content providers104, as well as a content delivery system 110 including a DNS serviceand multiple POPs;

FIG. 2 is a block diagram depicting an illustrative configuration of oneembodiment of a server that may implement the DNS service of FIG. 1;

FIG. 3A is a block diagram depicting interactions between an accessingcomputing device and the DNS service of FIG. 1 to resolve a distributionidentifier into a network address including encoded DNS-levelinformation;

FIG. 3B is a block diagram depicting interactions between an accessingcomputing device and a POP of FIG. 1 to provide content corresponding toa distribution identifier via a network address including encodedDNS-level information; and

FIG. 4 is an illustrative visualization of a format for encodingDNS-level information into a network address.

DETAILED DESCRIPTION

Generally described, aspects of the present disclosure relate to theutilization of specifically formatted network addresses in order tofacilitate the retrieval and transmission of content on a contentdelivery system. More particularly, aspects of the present disclosureenable a domain name system (DNS) service to generate and use networkaddresses that include encoded information available to the DNS serviceat least at a time that a client computing device requests to resolve anidentifier, such as a domain name, into a corresponding network address.Such information may be generally referred to herein as “DNS-levelinformation” or “DNS-level data,” and may include, for example, a domainname that a client computing device requested to resolve, securityinformation (such as transport security layer [“TLS”] or secure socketslayer [“SSL”] certificates associated with a domain name), validityinformation (such as time-to-live, or “TTL,” information), or otherinformation available at a DNS service. In particular, a DNS service mayencode all or a portion of such DNS-level information within a networkaddress advertised by the DNS service (e.g., included within DNS recordsprovided by the DNS service), and thus make such DNS-level informationavailable to routers or other computing devices that receive requests tocommunicate with the network address. In this manner, these routers orother computing devices may gain access to the DNS-level information,which would otherwise not be communicated to the routers or othercomputing devices in a traditional request addressed to a networkaddress. Use of such information may enable more efficient operation ofsuch routers or other computing devices. For example, a router orcomputing device may directly obtain a domain name to which a requestrelates from a network address of the request, without relying onexternal information or mappings. As another example, a router orcomputing device may determine whether a request to communicate with anetwork address should be considered valid, based on validityinformation encoded into the network address. Should the request beinvalid (e.g., due to an expired TTL), the request can be handled aserroneous or potentially malicious, thus enabling the router orcomputing device to determine validity as a function of a networkaddress, potentially without referencing external information regardingthe request. Thus, aspects of the present disclosure significantlyincrease the amount of information available to a computing device orrouter based on a network address, and enable such routers or computingdevices to more efficiently handle network communications by utilizingthis newly-available information.

Aspects of the present disclosure may be utilized, for example, by acontent delivery system hosting content of a multitude of entities. Sucha content delivery system can function to provide client computingdevices with access to a variety of different sets of content hosted bythe content delivery system on behalf of third-party content providersor an operator of the content distribution service itself. Such a set ofcontent can be generally referred to as a “distribution,” and maycorrespond to a specific web site (e.g., as associated with a specificdomain name) or other network-accessible service. Content deliverysystems generally make distributions available at one or more networkaddresses (e.g., internet protocol or “IP” addresses), to which acomputing device—either legitimate or malicious—may transmit a requestfor information. Traditionally, such network addresses are very limitedin the amount of information they convey, because the network addressesare generally formatted to identify one or more destination computingdevices on a network, and in some instances to assist in routingrequests to those destination computing devices. However, due to thelimited number of possible network addresses under some formats, such asIPv4, it was common to utilize the same network address to providemultiple sets of content (e.g., web sites). Thus, the same IPv4 addressmay identify an endpoint for many different distributions, which may ormay not be associated with one another. Such scenarios presentednumerous difficulties. For example, in a scenario where a specific website was under a denial of service (“DOS”) attack, data packets used toimplement the attack could be addressed to a network address associatedwith many different web sites, making it difficult or impossible todetermine the specific web site under attack based solely on the networkaddress to which malicious data packets were addressed. Prior patentfilings, such as U.S. Pat. No. 10,097,566, entitled “IDENTIFYING TARGETSOF NETWORK ATTACKS,” and issued Oct. 9, 2018, the entirety of which ishereby incorporated by reference, sought to address such shortcomingsby, for example, providing web sites with unique or substantially uniquecollections of network addresses.

The present application provides an additional or alternative solutionto the above-noted problems, among others. Specifically, embodiments ofthe present disclosure can utilize one or more encoding rules to encodeDNS-level data, such as a domain name to which a DNS request isdirected, into a network address. Thus, a router or other computingdevice receiving a data transmissions addressed to the network addressmay decode the network address itself in order to obtain the encodedDNS-level data. Illustratively, encoding of DNS-level data into anetwork address can enable routers or other computing devices todetermine, from a network address to which a data packet is addressed,what domain name was included within a DNS request that precededgeneration of the data packet. Advantageously, DNS-level data maytherefore be determined subsequent to DNS resolution, without relying onindependent or additional communication with a DNS service, and withoutrelying on the content of data packets themselves (which, particularlyin the case of network attacks, may be malformed). For example, acomputing device may determine that malicious data packets transmittedto a given network address are the result of a DNS resolution of aparticular domain name, and thus may further determine that thedistribution associated with the domain name is the target of a networkattack. The computing device may then take mitigating action to reduceor eliminate negative effects of the network attack.

Because the present disclosure enables encoding of DNS-level informationinto network addresses, embodiments of the present disclosure may beparticularly suited for implementation with respect to network addressformats having a large address space. One example of such a networkaddress format is the IPv6 format, which utilizes 128 bit networkaddresses. The large number of potential network addresses within theIPv6 format (particularly in comparison to the IPv4 format) can enableDNS-level information to be encoded without negatively impacting thetraditional identification and routing functions of network addresses.

While examples are provided above enabling domain names to be encodedinto network addresses, other DNS-level information may additionally oralternatively be encoded into a network address under the presentdisclosure. For example, a DNS service may encode within a networkaddress “hint information,” that enables a router or other computingdevice (e.g., a server within a POP) to more efficiently servicerequests to communicate with the network address. Illustratively, thehint information may include an identifier of a security certificate(e.g., and SSL or TLS certificate) associated with a domain name towhich the request is directed. Accordingly, when a computing devicereceives a request to communicate with a network address includingencoded hint information, the computing device may decode the hintinformation, determine the security certificate identified by the hintinformation, and establish a secure communication channel with a clientcomputing device. In some instances, encoding of hint information withina network address may reduce or eliminate the need for a router or othercomputing device (e.g., of a CDN) to maintain a mapping of networkaddresses to associated security certificates, or to inspect datapackets for information identifying a relevant security certificate(e.g., a “host header” within an HTTP packet). Because decoding of hintinformation within a network address may require less processing poweror memory usage than would packet inspection or using lookups toexternal mappings, use of hint information can reduce the computingresources used by a router or other computing device.

Additional examples of hint information may include a network address orother information of a device from which a DNS resolution request wasreceived (e.g., an accessing computing device, a DNS resolver used bythat accessing computing device, etc.). In some instances, components ofa CDN may use such information to determine how to handle subsequentrequests to access content, stemming from an initial DNS resolutionrequest. For example, where request to access content results in a“cache miss” at a POP of a CDN (e.g., where an accessing computingdevice requests content not stored at the POP), a POP can be configuredto retrieve the requested information from another server (sometimesreferred to as an “origin server”). Where the content is available atmultiple origin servers, the POP may in some instances use hintinformation to select an appropriate origin server. For example, where acontent request is addressed to a network address with hint informationidentifying a particular geographic or network location (e.g., as theregion from which a corresponding DNS request originated), the POP mayselect an origin server nearby to that geographic or network locationfrom which to obtain the relevant content.

In some embodiments, DNS-level information may further include validityinformation encoded into a network address by a DNS service. When suchvalidity information is encoded into a network address, and a clientcomputing device attempts to communicate with a destination computingdevice (e.g., a server within a POP) associated with the networkaddress, that destination computing device may verify the validityinformation prior to initiating communication with the client computingdevice. In this way, a DNS service and a destination computing devicemay work cooperatively to ensure that all client computing devicesaccessing the destination computing device are legitimate users of theDNS service. Such cooperation may assist, for example, in mitigatingnetwork attacks. For example, some types of DoS attack function byinstructing a first device to resolve a domain name of an attack targetinto an IP address using a DNS service, and then instructing a largenumber of additional devices to transmit malicious data packets to theIP address. These additional devices do not interact directly with theDNS service, but instead repeat IP address information maintained by thefirst device. Thus, embedding validity information within an IP addressthat is tied specifically to the first device may enable an attacktarget (or other computing device) to distinguish between the firstdevice and the additional device, substantially reducing the volume ofattack traffic.

Further, network attacks are in some instances “non-re-resolving,” suchthat resolution of a domain name of an attack target into a networkaddress occurs only once (or very infrequently). Thus, changes to DNSrecords for an attack target, such as changing the network address ofthe attack target, can function to redirect legitimate traffic to a newnetwork address while malicious traffic continues to flow to the defunctnetwork address. To reduce the effect of such malicious traffic, somesystems may modify configurations of routers or other computing devicesto halt processing of traffic directed to a defunct network address.Such halting is sometimes referred to as “blackholing” the defunctnetwork address, and generally involves discarding or “dropping” packetsaddressed to the defunct network address, either at a receivingcomputing device or at an intermediary network device. Traditionalcreation of a blackhole network address generally involves propagationof new routing information (e.g., routing tables, such as a forwardinginformation base or “FIB”) across a network, a process that introducesadditional traffic into a network and therefore can utilize significantcomputing resources. By inclusion of validity information into a networkaddress, blackholing can be automated without requiring distribution ofnew routing information across a network. Rather, each device on anetwork may be configured such that any packet with invalid validityinformation is automatically dropped by a router or other computingdevice. In some instances, the protocol by which validity information isgenerated or verified may be modified over time, such as on an hourlybasis. Thus, a network attacks that continue after modification ofvalidity information, without re-resolving a domain name into acorresponding valid network address, would result in data packets beingtransmitted to an invalid network address, and such data packets couldbe automatically dropped within a network. Thus, the inclusion ofvalidity information within a network address can enable computingdevices to readily and efficiently distinguish legitimate fromillegitimate traffic.

While illustrative examples of DNS-level information are provided above,a network address encoded according to embodiments of the presentdisclosure may include additional or alternative DNS-level data. Forexample, a DNS service may in some instances encode a unique “requestidentifier” into each network address provided in response to a DNSrequest, in order to uniquely identify content requests that stem fromthe DNS request. Thereafter, data can be collected from both the DNSservice and corresponding POPs of a CDN, in order to determinecorrelations between DNS requests and subsequent content requests. Forexample, the CDN may determine that a given DNS request resulted in ncontent requests to the network address referenced in the DNS request.Thus, the examples of DNS-level data provided herein are illustrative innature.

To enable encoding and decoding of information within a network address,a DNS service and a destination computing device (e.g., a deviceassociated with a network address identified within a DNS record, whichmaps a domain name or other identifier to a network address) can eachmaintain one or more rules indicating how information is encoded withina network address. The rules may specify, for example, which bits of anetwork address represent different types of DNS-level information, andhow that information is represented. Illustratively, a rule may specifythat the last 16 bits of a network address represent an identifier of adistribution associated with the network address (e.g., a domain name orother unique identifier of the distribution). A rule may further specifythat the penultimate 16 bits of a network address represent validityinformation for the network address, hint information, etc. For eachtype of information encoded within a network address, the rule mayspecify how that information is encoded. For example, a domain name maybe encoded by processing the domain name according to a hash algorithm,to result in a hash value of the corresponding number of bits.Thereafter, the hash value may be included in a network address as anencoded domain name. In some instances, information may be encodedaccording to a cryptographic hash algorithm, such as an algorithm of theSecure Hash Algorithm family (e.g., SHA-2 or SHA-3) or an algorithm ofthe Message-Digest Algorithm family (e.g., MD6). For example, validityinformation may be generated by passing some set of inputs (e.g., valuesof the remaining fields encoded within a network address, a currenttime, an identifier of a client computing device, etc.) through acryptographic hash to produce a digest, and then encrypting the digestwith a private key to produce a digital signature that can be includedin the validity information. The process of utilizing cryptographichashes and encoding via private keys to result in digital signatures issometimes referred to as “public key cryptography” or “asymmetriccryptography.” This process is known in the art and therefore will notbe described in detail herein. However, with application to theembodiments of the present disclosure, the use of public keycryptography to generate digital signatures for inclusion in a networkaddress can provide substantial certainty that any valid network address(e.g., with a verifiable digital signature) was obtained by interactionwith a DNS service that had access to a corresponding private key.

In some instances, all or a portion of a network address may beencrypted, to avoid conveyance or modification of information tounauthorized parties. For example, DNS-level data (e.g., including adigital signature value) may be encrypted according to public keyencryption. Illustratively, a DNS service may utilize a public keyassociated with a content server to encrypt DNS-level data of a networkaddress (or any given portion of a network address), and the contentserver, on receiving data addressed to the network address, may utilizea corresponding private key to decrypt the portion and utilize theDNS-level data (or other data represented by the portion) in provide therequested information. As a further illustration, a router of the CDNmay utilize a corresponding private key to decrypt a network address towhich data is addressed, and utilize a decrypted value to route the dataon the CDN. Encryption of DNS-level data (or other values represented innetwork addresses) may be beneficial in preventing authorized entitiesfrom obtaining knowledge of actual network addresses utilized within theCDN (e.g., where the decrypted network address represents a networkaddress of a content server), or obtaining knowledge of DNS-level dataencoded within a network address. In some embodiments, digitalsignatures and encryption of network address information may be used inconjunction to provide confidentiality, integrity, and authenticity ofthe network address. To ensure routability of data addressed to anencrypted network addresses, a portion of such network addresses (e.g.,a routing prefix) may be left encrypted.

In some instances, network addresses may be formatted to enable analteration of the rules for encoding information within those networkaddresses. For example, one or more bits of a network address may beassigned to represent a version identifier, indicative of a format ofthe network address. On receiving a request from a client computingdevice to communicate with a network address, a destination device mayinspect the version identifier to determine corresponding rules,indicative of how DNS-level information is encoded within the networkaddress. Thus, a DNS service and corresponding CDN may alter encodingrules for network addresses periodically, or in some instances utilizemultiple different encoding formats simultaneously. In one embodiment,the DNS service and CDN may identify “high risk” distributions,associated with a higher likelihood of being targeted in a networkattack, and provide a distinct set of encoding rules for network addressof these distributions. These rules, for example, may include strongervalidity information, or may by altered more rapidly than networkaddresses of other, non-high risk distributions. In some instances, therules may specify a similar or identical encoding format of information,but may vary other parameters used in such encoding. For example, therules may specify a particular public/private key pair to utilize inencoding network addresses. Version information encoded within a networkaddress can enable the DNS service and CDN to determine the rules underwhich a given network address has been encoded.

While the above description refers generally to a DNS service andcorresponding destination device (e.g., as part of a CDN) that eachmaintain knowledge of rules for encoding network addresses, someembodiments of the present disclosure may utilize a distinct service tomaintain such rules. Illustratively, both a DNS service and destinationdevices of a CDN may be provided with access to an applicationprogramming interface (API) of a network address encoding service, suchthat the DNS service and destination devices may transmit requests tothe network address encoding service to generate network addresses for agiven distribution or to decode DNS-level information from a networkaddress. Use of such a network address encoding service may, forexample, simplify requirements to synchronize rules between a DNSservice and destination devices.

While examples are provided herein with respect to content distributionsystems, embodiments of the present application may be implemented withrespect to any network of computing devices that operates to servediscrete sets of content to client computing devices. Moreover, whilesome examples are provided with respect to a content distributionnetwork as a whole, embodiments of the present application may also beimplemented in whole or in part by discrete portions of the contentdelivery system. Thus, the examples provided herein are intended to beillustrative, and not exhaustive, in nature.

As will be appreciated by one of skill in the art in light of thedescription above, the embodiments disclosed herein substantiallyincrease the ability of computing systems, such as content deliverysystems, to handle network communications. Specifically, embodimentsdisclosed herein enable more efficient routing or communication handlingby providing hint information directly within a network address,reducing or eliminating the need for routing or destination devices tomaintain such information separately. Moreover, embodiments disclosedherein enable identification of a specific set of content (adistribution) to which transmissions are directed, based on the networkaddress of the transmission and regardless of the contents of thetransmission. Still further, embodiments disclosed herein enableinclusion of validity information, such as a digital signature, within anetwork address, to assist in distinguishing legitimate communicationsfrom invalid and potentially malicious communications. Thus, thepresently disclosed embodiments represent an improvement in thefunctioning of such computing systems, by enabling content deliverysystems or other networked devices to more efficiently route and handlecommunications, to more efficiently identify and discard maliciouscommunications, and to continue to service legitimate client requestseven while receiving large numbers of illegitimate requests. Moreover,the presently disclosed embodiments address technical problems inherentwithin computing systems; specifically, the limited ability of computingsystems to process network-based requests, the reliance of traditionalnetwork routing technologies on external information when routingrequests to communicate with a network address, and the disassociationbetween a DNS service and a destination network device caused bycommonly used network communication protocols. These technical problemsare addressed by the various technical solutions described herein,including the encoding at a DNS service of DNS-level data within anetwork address, the decoding of such information at a destinationdevice, and the use of such information to handle requests tocommunicate with the network address. Thus, the present applicationrepresents a substantial improvement on existing network systems andcomputing systems in general.

The foregoing aspects and many of the attendant advantages of thepresent disclosure will become more readily appreciated as the samebecome better understood by reference to the following, when taken inconjunction with the accompanying drawings.

FIG. 1 is a block diagram depicting an illustrative logical network 100including multiple accessing computing devices 102 and multiple contentproviders 104 in communication with a content delivery system 110 via anetwork 106. As shown in FIG. 1, the content delivery system 110includes a DNS service 112 enabling accessing computing devices 102 toresolve identifiers of distributions on the content delivery system 110(e.g., domain names) into network addresses. The content delivery system110 further includes one or more points-of-presence (POPs) providingaccess to content of the distributions on the content delivery system110. While the accessing computing devices 102 and the content providers104 are shown as a group within FIG. 1, the accessing computing devices102 and content providers 104 may be geographically distant, andindependently owned or operated. For example, the accessing computingdevices 102 could represent a multitude of users in various global,continental, or regional locations accessing the content delivery system110. Further, the content providers 104 could represent a multitude ofrelated or distinct parties that have associated with the contentdelivery system 110 to provide content, such as web sites, multimedia,or other digital, network-deliverable content to the accessing computingdevices 102. Accordingly, the groupings of accessing computing devices102 and content providers 104 within FIG. 1 is intended to represent alogical, rather than physical, grouping. Similarly, each of thecomponents of the content delivery system 110 may be located withingeographically diverse areas. For example, the DNS service 112 and POPs124 within the content delivery system 110 may be globally,continentally, or regionally disparate, in order to provide a widegeographical presence for the content delivery system 110.

Network 106 may be any wired network, wireless network, or combinationthereof. In addition, the network 106 may be a personal area network,local area network, wide area network, cable network, satellite network,cellular telephone network, or combination thereof. In the exampleenvironment of FIG. 1, network 106 is a global area network (GAN), suchas the Internet. Protocols and components for communicating via theother aforementioned types of communication networks are well known tothose skilled in the art of computer communications and thus, need notbe described in more detail herein. While each of the accessingcomputing devices 102, content providers 104, and content deliverysystem 110 is depicted as having a single connection to the network 106,individual components of the accessing computing devices 102, contentproviders 104, and content delivery system 110 may be connected to thenetwork 106 at disparate points. Accordingly, communication times andcapabilities may vary between the components of FIG. 1.

Accessing computing devices 102 may include any number of differentcomputing devices capable of communicating with the content deliverysystem 110. For example, individual accessing computing devices maycorrespond to a laptop or tablet computer, personal computer, wearablecomputer, server, personal digital assistant (PDA), hybrid PDA/mobilephone, mobile phone, electronic book reader, set-top box, camera,digital media player, and the like. Further, accessing computing devices102 may include devices utilized by both legitimate clients of thecontent delivery system 110 and devices utilized by malicious parties toundertake network-based attacks, such as DoS attacks, on the contentdelivery system 110.

Content providers 104 may include any computing device owned or operatedby an entity that has provided content to the content delivery system110 for subsequent transmission to client computing devices (which mayinclude one or more accessing computing devices 102). For example,content providers 104 may include servers hosting web sites, streamingaudio, video, or multimedia services, data analytics services, or othernetwork-accessible services. While illustratively shown in FIG. 1 as anetwork-attached computing device, content providers 104 mayadditionally or alternatively provide content to the content deliverysystem 110 via non-networked communication channels (e.g., via physicaldelivery of data).

The content provided to the content delivery system 110 by the contentproviders 104 may be wholly or partially hosted in POPs 120. Each POP120 may include a variety of computing devices configured to servecontent to accessing computing devices 102. Specifically, each POP 120may include one or more content servers 122 associated with networkaddresses to which accessing computing devices 102 may address requeststo obtain content from the content delivery system 110. Each POP 120 mayfurther include a data cache 126 on which such content can be stored.Because the amount of storage space of each data cache 126 may belimited, content servers 122 of the POPs 112 can be configured to detect“cache misses”—instances in which data requested by an accessingcomputing device 102 is not available in the data cache 126—and toretrieve such data from another device (e.g., the content providers 104or other data stores not shown in FIG. 1). Thus, the content servers 112may be logically viewed as “edge” devices, providing a first-level cacheof content on the content delivery system 110. The general operation ofcontent servers 112 within a POP 120 to obtain and provide content isknown within the art, and therefore will not be described in detailherein. In accordance with embodiments of the present disclosure, eachPOP 120 may further include a decoding rules data store 124 configuredto store one or more rules indicating how DNS-level data is encoded intonetwork addresses. As will be described below, such rules may indicatethe specific bits of a network address that represent different types ofDNS-level information, and the algorithms or encoding by which suchinformation is encoded.

Each POP 120 may be associated with a number of network addresses viawhich accessing computing devices 102 may address the POP 120 via thenetwork 106. In one embodiment, each network address is an internetprotocol version 6 (IPv6) address. For example, each POP 114 may beassociated with one or more specific “blocks” of network addresses, suchas the “2001:db8::/48” block of IPv6 addresses (represented in classlessinter-domain routing or “CIDR” notation, as is common in the art).Further, each POP 120 may be configured to provide multiple sets ofcontent, each of which may be associated with a specific contentprovider 104. Generally, these discrete sets of content may be referredto herein as a “distribution.” Each distribution may represent aspecific network-accessible service, such as a web site, available fromthe POP 114 or the content delivery system 110 generally. As describedbelow, network addresses encoded with DNS-level information may includea first section, sometimes referred to as a routing prefix,corresponding to the block of network addresses associated with a POP120. Thus, communications transmitted to these network addresses via thenetwork 106 would be expected to arrive at the POP 120 associated withthe routing prefix. One or more remaining bits of such network addresses(e.g., other than the routing prefix) may be used to designate adistribution of the content delivery system 110 from which content isrequested, as well as other information utilizable by the contentservers 112 to handle requests to communicate with the networkaddresses.

The illustrative content delivery system 110 of FIG. 1 further includesa DNS service 112 configured to enable accessing computing devices 102to resolve human-readable network identifiers of distributions (such asdomain names or URLs) into network addresses (such as IP addresses)encoded with DNS-level information, to which requests to access contentof a distribution may be transmitted. Specifically, the DNS service 112includes one or more DNS servers 114, each including one or moreprocessors, memories, and data storage devices collectively configuredto receive requests from accessing computing devices 102 for a specificdomain name associated with a distribution. The DNS servers 112 mayfurther be configured, in response, to provide one or more networkaddresses, associated with one or more computing devices within a POP120, at which content of that distribution may be obtained. Inaccordance with embodiments of the present disclosure, such networkaddresses may include encoded DNS-level information (e.g., informationavailable at the DNS service 112 at least at the time of the request).Thereafter, the accessing computing device 114 may communicate with thePOP 120, via the network addresses, to access the distribution. In oneembodiment, network addresses corresponding to an identifier of contenton the content distribution system 110 (a “distribution identifier,”which may correspond, for example, to a domain name or uniform resourceidentifier [“URI”]) may be included within DNS records pre-generated bythe DNS service 112, and stored within a DNS record data store 119.Illustratively, one or more DNS servers 114 may generate DNS recordsbased on one or more rules included within the encoding rules data store116, which rules specify the format of network addresses encoded withDNS-level information, as well as information regarding a distributionto which the network address should correspond. Such information may bestored, for example, within the distribution data store 118, and maycomprise prefix information for one or more POPs 120 at which thedistribution can be accessed, hint information for the distribution(e.g., an identifier of a security certificate applicable to thedistribution, an identifier of a resolver from which a corresponding DNSrequest was received or a location of that resolver, etc.), identifiersof rules applicable to the distribution, etc. For example, the DNSservice 112 may identify a prefix associated with a POP 120 from whichthe distribution can be accessed in order to determine the first portionof a network address for the distribution. The DNS service 112 mayfurther utilize the one or more rules to determine a set of bitscorresponding to an identifier of the distribution, a set of bitscorresponding to hint information for the distribution, a set of bitscorresponding to validity information for the network address, and a setof bits corresponding to a version identifier for the one or more rules.The DNS service 112 may then concatenate the prefix, set of bits for theidentifier, set of bits for the hint information, set of bits for thevalidity information, and the set of bits for the version identifier toresult in a network address in an applicable format specified under theone or more rules (e.g., IPv6). The DNS server 112 may then store a DNSrecord associating the identifier of the distribution with the generatednetwork address with the DNS record data store 119. When a request isobtained from an accessing computing device 102 to resolve theidentifier of the distribution, the DNS server 112 may retrieve a DNSrecord corresponding to the identifier (e.g., identifying one or morenetwork addresses mapped to the identifier), and return the DNS recordto the accessing computing device 102. In some instances, a DNS server112 may generate DNS records for a distribution periodically (e.g.,every hour). In other instances, a DNS server 112 may generate DNSrecords for a distribution “on-the-fly,” in response to requests fromaccessing computing devices 102 to resolve a distribution identifier.Such on-the-fly record generation may be beneficial, for example, inorder to allow for use of request-specific information during generationof a network address. For example, in some instances, a DNS server 114may use a region identifier associated with a resolution request (e.g.,an identifier of a geographical or logical region from which theresolution request stemmed) as an input to an algorithm for generatingvalidity information for a network address, such that POPs 120 respondto requests to communicate with the network address only if suchrequests stem from the same region.

The encoding rules data store 116, distribution data store 118, and DNSrecord data store 119 of the DNS service 112, as well as the decodingrules data store 124 and data cache 126 of the POPs 120, may correspondto any persistent or substantially persistent data storage, such as ahard drive (HDD), a solid state drive (SDD), network attached storage(NAS), a tape drive, or any combination thereof.

As noted above, while the encoding and decoding of DNS-level data intoor from network addresses is generally described with reference to theDNS server 112 and POPs 120, either or both the DNS server 112 and POPs120 may in some embodiments utilize an external address encoding service(not shown in FIG. 1) to encode or decode DNS-level data into or fromnetwork addresses. For example, the address encoding may include one ormore servers configured to provide an API or other interface throughwhich requests may be received to encode DNS-level data into a networkaddress of a distribution, or to decode DNS-level data from a networkaddress. Such servers may be in communication with a rules data store,and utilize rules from such a data store to encode or decode networkaddresses, in accordance with embodiments of the present disclosure.

It will be appreciated by those skilled in the art that the contentdelivery system 110 may have fewer or greater components than areillustrated in FIG. 1. In addition, the content delivery system 110could include various web services and/or peer-to-peer networkconfigurations. Thus, the depiction of the content delivery system 110in FIG. 1 should be taken as illustrative. For example, in someembodiments, components of the content delivery system 110, such as theDNS server 112, may be executed by one more virtual machines implementedin a hosted computing environment. A hosted computing environment mayinclude one or more rapidly provisioned and released computingresources, which computing resources may include computing, networkingand/or storage devices. A hosted computing environment may also bereferred to as a cloud computing environment.

Any one or more of the DNS servers 112, encoding rules data store 116,DNS record data store 119, distribution data store 118, content servers122, decoding rules data store 124, and data cache 126 may be embodiedin a plurality of components, each executing an instance of therespective DNS servers 112, encoding rules data store 116, DNS recorddata store 119, distribution data store 118, content servers 122,decoding rules data store 124, and data cache 126. A server or othercomputing component implementing any one of DNS servers 112, encodingrules data store 116, DNS record data store 119, distribution data store118, content servers 122, decoding rules data store 124, and data cache126 may include a network interface, memory, processing unit, andcomputer readable medium drive, all of which may communicate which eachother may way of a communication bus. The network interface may provideconnectivity over the network 106 and/or other networks or computersystems. The processing unit may communicate to and from memorycontaining program instructions that the processing unit executes inorder to operate the respective DNS servers 112, encoding rules datastore 116, DNS record data store 119, distribution data store 118,content servers 122, decoding rules data store 124, and data cache 126.The memory may generally include random access memory (RAM), read onlymemory (ROM), other persistent and auxiliary memory, and/or anynon-transitory computer-readable media.

FIG. 2 depicts one embodiment of an architecture of a server 200 thatmay implement a DNS server 114 of the DNS service 112 or othercomponents described herein. The general architecture of server 200depicted in FIG. 2 includes an arrangement of computer hardware andsoftware components that may be used to implement aspects of the presentdisclosure. As illustrated, the server 200 includes a processing unit204, a network interface 206, a computer readable medium drive 207, aninput/output device interface 220, a display 222, and an input device224, all of which may communicate with one another by way of acommunication bus. The network interface 206 may provide connectivity toone or more networks or computing systems, such as the network 106 ofFIG. 1. The processing unit 204 may thus receive information andinstructions from other computing systems or services via a network. Theprocessing unit 204 may also communicate to and from memory 210 andfurther provide output information for an optional display 222 via theinput/output device interface 220. The input/output device interface 220may also accept input from the optional input device 224, such as akeyboard, mouse, digital pen, etc. In some embodiments, the server 200may include more (or fewer) components than those shown in FIG. 2. Forexample, some embodiments of the server 200 may omit the display 222 andinput device 224, while providing input/output capabilities through oneor more alternative communication channel (e.g., via the networkinterface 206).

The memory 210 may include computer program instructions that theprocessing unit 204 executes in order to implement one or moreembodiments. The memory 210 generally includes random access memory(RAM), read only memory (ROM) and/or other persistent or non-transitorymemory. The memory 210 may store an operating system 214 that providescomputer program instructions for use by the processing unit 204 in thegeneral administration and operation of the server 200. The memory 210may further include computer program instructions and other informationfor implementing aspects of the present disclosure. For example, in oneembodiment, the memory 210 includes user interface software 212 thatgenerates user interfaces (and/or instructions therefor) for displayupon a computing device, e.g., via a navigation interface such as a webbrowser installed on the computing device In addition, memory 210 mayinclude or communicate with one or more auxiliary data stores, such asdata store 226, which may correspond to any persistent or substantiallypersistent data storage, such as a hard drive (HDD), a solid state drive(SDD), network attached storage (NAS), a tape drive, or any combinationthereof. Illustratively, the data store 226 may correspond to theencoding rules data store 116, the DNS record data store 119, thedistribution data store 118, or any combination thereof.

In addition to the user interface module 212, the memory 210 may includeaddress encoding software 216 that may be executed by the processingunit 204. In one embodiment, the address encoding software 216implements various aspects of the present disclosure, e.g., thegeneration DNS records including network address encoded with DNS-levelinformation.

With reference to FIGS. 3A and 3B, a set of illustrative interactionswill be described for the generation and use of network addressesencoded with DNS-level information on a content delivery system 110.Specifically, FIG. 3A depicts illustrative interactions for thegeneration of DNS records mapping a distribution identifier to a networkaddress encoded with DNS-level information, and for transmission of sucha DNS record to an accessing computing device 102A. FIG. 3B depictsillustrative interactions for the handling of a communication requestfrom the accessing computing device 102A to the network address encodedwith DNS-level information. For the ease of illustration, theinteractions of FIGS. 3A and 3B will be described with reference to anindividual accessing computing device 102A requesting to access anindividual distribution on the content delivery system 110, and withreference to an individual network address of that distribution.However, similar interactions may occur in some embodiments with respectto multiple accessing computing devices 102A (accessing one or moredistributions), multiple distributions, multiple network addresses for agiven distribution, or any combination thereof.

The interactions of FIG. 3A begin at (1), where the DNS service 112loads encoding rules for encoding DNS-level information of adistribution into a network address. Illustratively, such rules may beloaded from the encoding rules data store 116. In some instances, theloaded rules may be generally static or constant across time ordistributions. In other instances, the loaded rules may differ based onthe specific distribution (e.g., as a high risk or non-high riskdistribution), based on the time of day (e.g., to vary network addressformats to prevent knowledge by unauthorized devices), or based on othercriteria. Thereafter, at (2), the DNS service 112 encodes DNS-level datainto a network address according to the obtained rules. Illustratively,the DNS service 112 may determine one or more fields for DNS-levelinformation specified by the rules, generate data corresponding to eachfield according to an algorithm specified in the rule, and concatenatethat data according to an ordering specified within the rule to resultin a network address. Thereafter, at (3), the DNS service 112 cangenerate a DNS record mapping an identifier of the distribution, such asa domain name, to the network address encoded with DNS-level data, andstore the DNS record within the DNS record data store 119.

Further detail regarding the generation of network addresses withencoded DNS-level data will be described with reference to FIG. 4, whichis an illustrative visualization or graphical depiction of a potentialformat for network addresses with encoded DNS-level data. Specifically,FIG. 4 depicts an illustrative format for a 128 bit network address,which may conform, for example, to the IPv6 format. For ease ofdepiction, the 128 bit network address of FIG. 4 is divided into 8logical bit groups, each corresponding to 16 of the 128 bits of thenetwork address. Each field of DNS-level data within an encoded networkaddress may be represented by the values of bits within a given bitgroup. For example, as shown in FIG. 4, the first 48 bits of the networkaddress may be used to represent a routing prefix. Each routing prefixmay be associated, for example, with one or more POPs 120, such thatnetwork packets addressed to any network address with a given prefixwill be routed via the network 106 to the corresponding POP 120 to whichthe prefix is assigned. Illustratively, the length and content of therouting prefix may be collectively agreed on by participants in thenetwork 106, and thus the DNS service 112 may be configured to maintainsuch prefixes without encoding DNS-level data into the prefixes. Asshown in FIG. 4, all or a portion of the remaining bits of a networkaddress (e.g., other than the routing prefix) may be used to representencoded DNS-level information. For example, bit group 8 (the final 16bits of the network address) may be used to uniquely identify adistribution associated with the network address. Illustratively, whereeach distribution on the content delivery system 110 is associated witha unique identifier representable in 16 bits or less, a network addressencoded according to the format of FIG. 4 may directly represent thatunique identifier within bit group 8. Where each distribution on thecontent delivery system 110 is associated with a unique identifier thatmay or may not be representable in 16 bits or less (e.g., a domain nameof arbitrary length), a network address encoded according to the formatof FIG. 4 may represent that unique identifier as a hash value,generated by passing the unique identifier through a hashing function.The specific number of bits utilized to represent a distributionidentifier may vary, for example, on the number of differentdistribution identifiers supported under a given format, and theprobability of collisions between different identifiers under a givenencoding scheme. On receiving a request to communicate with the networkaddress, a receiving device (e.g., a content server 122) may identifythe distribution to which the request is directed based on the final bitgroup of the network address. Additional DNS-level information that maybe included within a network address according to the illustrativeformat of FIG. 4 includes a rule identifier represented by bit group 4,validity information represented by bit group 5, and hint informationrepresented by bit group 6. Illustratively, the bits of group 4,representing a rule identifier, may identify a rule that describes thenetwork address encoding format shown in FIG. 4 (e.g., identifier“0001”), and may be used to identify network addresses encoded accordingto the network address encoding format shown in FIG. 4 from otherpotential formats. Thus, on receiving a request to communicate with thenetwork address, a receiving device (e.g., a content server 122) mayidentify the format of the network address according to the bits ofgroup 4 (e.g., enabling the receiving device to obtain rules specifyinghow other DNS-level data is encoded into the network address). The bitsof group 5, representing validity information, may represent a digitalsignature generated based on a private key of the DNS service 112 alongwith a set of inputs, which may include, for example, the values ofother bit groups of the network address. Thus, on receiving a request tocommunicate with the network address, a receiving device (e.g., acontent server 122) may verify the validity of the network address byconfirming the digital signature (e.g., decrypting the digital signatureusing a corresponding cryptographic public key and comparing a resultingvalue to an independent hash of the same set of inputs). The bits ofgroups 6 and 7, representing hint information, may represent informationinforming a receiving device of how to handle requests to communicatewith the network address, such as an identifier of a securitycertificate to utilize in creating a secure communication channel withan accessing computing device 102. Thus, on receiving a request tocommunicate with the network address, a receiving device (e.g., acontent server 122) may retrieve a security certificate corresponding tothe hint information and use such a certificate to establish securecommunications with the accessing computing device 102. Additionalexamples of hint information may include, for example, an identifier ornetwork address of a resolver from which a DNS request corresponding tothe encoded network address was received, a location of that resolver,etc.

While one potential format of a network address with encoded DNS-levelinformation is shown in FIG. 4, other formats are possible andcontemplated under the present disclosure. For example, more than 48bits may be included within a routing prefix, or an additional bit group(e.g., bit group 4) may be used as a subnet prefix, in accordance withIPv6 protocols. Moreover, the specific bits used to identify each typeof DNS-level data may vary according to different potential formats.While these bits are shown in FIG. 4 as 16-bit groups for ease ofdescription, any number of bits may be used to identify each type ofDNS-level data. For example, less than 16 or 32 bits may be sufficientto store a rule identifier or hint information, respectively (e.g., inthe instance where less 65,536 total rule identifiers or 2³² hintinformation values are intended to be supported). More than 16 bits maybe used to store validity information (e.g., according to a strength ofsecurity desired) or distribution identifiers (e.g., according to thenumber of identifiers supported and a potential for collisions should ahash function be utilized). Any number of algorithms, including avariety of known hash algorithms, may be utilized to determine the bitvalues representative of given DNS-level data. Thus, the size, content,and arrangement of DNS-level data as encoded into a network address mayvary.

As noted above, all or a portion of a network address may be encrypted.For example, the values of any one or more of bit groups 4 through 8 asshown in FIG. 4 may be encrypted according to public key encryption(using a public key) to represent an encrypted bit group, and a networkaddress may be returned including at least one encrypted bit group.Thereafter, the values of the encrypted bit groups may be decryptedutilizing a corresponding private key, to determine the unencryptedvalues of the bit groups. Illustratively, a DNS server 112 may beconfigured to provide network addresses including at least one encryptedbit group within a DNS response, and one or more routers of the contentdelivery system 110 may be configured to decrypt the bit groups onreceiving a data packet addressed to a network address including anencrypted bit group. In one embodiment, the router may validate orverify integrity of the network address (e.g., using validityinformation encoded into the network address, such as a digitalsignature), before forwarding the data packet within the contentdelivery system 110 (e.g., utilizing the unencrypted network address).In this manner, the network addresses utilized within the contentdelivery system 110 may be kept confidential to devices outside of thecontent delivery system 110 (or without a private key utilized by thecontent delivery system 110). While DNS-level information may beencrypted as described above, other data conveyed by a network addressmay additionally or alternatively be encrypted. For example, where anetwork assigns network addresses sequentially, randomly, or via anotherdistribution mechanism, all or a portion of such network addresses maybe encrypted before being provided in a DNS response, and a receivingdevice (e.g., a content server 112, a router, etc.) may be configured todecrypt the network address on receiving a data packet addressed to theencrypted network address

Returning to the interactions of FIG. 3A, once a DNS record for adistribution has been created, the DNS service 112 may function toobtain requests to resolve an identifier of the distribution from anaccessing computing device 102A, as shown at (4). While this request isshown in FIG. 3A as beginning at the accessing computing device 102A andterminating at the DNS service 112, the request may be transmittedaccording to well-known DNS transmission protocols, and thus may passthrough any number of intermediary devices (e.g., DNS resolvers) priorto arriving at the DNS service 112. Thus, the DNS service 112 may not bedirectly aware of the identity of the accessing computing device 102A.

At (5), in response to the request, the DNS service 112 may return theDNS record referencing the network address encoded with DNS-level data.Similarly to interaction (4), while this response is shown as beginningat the DNS service 112 and terminating at the accessing computing device102A, the response may be transmitted according to well-known DNStransmission protocols, and thus may pass through any number ofintermediary devices (e.g., DNS resolvers) prior to arriving at theaccessing computing device 102A. On receiving the DNS record, theaccessing computing device 102A may then transmit network data to thenetwork address referenced in the DNS record, as will be described withreference to FIG. 3B.

While a simplified set of interactions are described with reference toFIG. 3A, additional or alternative interactions may occur underembodiments of the present disclosure. For example, the DNS service 112may in some instances maintain multiple DNS records for a distribution(e.g., each including a network address associated with a different POP120), and distribute the DNS records according to a load balancing ortraffic shaping algorithm (e.g., round robin). As a further example, theDNS service 112 may in some instances operate to generate or modify DNSrecords on-the-fly, in response to requests to resolve a distributionidentifier. For example, the DNS service 112 may generate validity datafor a network address based at least in part on attributes of therequest, such as a geographic or logical region from which the requestwas received. As another example, the DNS service 112 may in someinstances modify a TTL value for a DNS record to corresponding to alength of time until the DNS service 112 is configured to generate newvalidity data for network addresses of a distribution associated withthe DNS record. In this way, where accessing computing device 102Acomply with the TTL value of the DNS record, these devices can beexpected to consider a DNS record expired at or before the contentdelivery system 110 would consider the network address in the record asinvalid due to a change in validity information. Thus, differentaccessing computing devices 102 may obtain different DNS records fromthe DNS service 112, even when requesting to resolve the samedistribution identifier, and the ordering and content of theinteractions of FIG. 3A should be viewed as illustrative in nature.

With reference to FIG. 3B, illustrative interactions will be describedfor the handling of a communication request from the accessing computingdevice 102A to the network address encoded with DNS-level information.For ease of reference, the interactions of FIG. 3B are numbered insequence with those of FIG. 3A; however, the interactions of FIGS. 3Aand 3B may in some instances occur separately (e.g., in the case of anetwork attack, where multiple accessing computing devices 102A maytransmit data to a network address obtained by DNS request of adifferent accessing computing device 102A).

The interactions of FIG. 1 begin at (6), where the accessing computingdevice 102A transmits a request to access content of a distribution to anetwork address including encoded DNS-level data (e.g., as referencedwithin a DNS record obtained from the DNS service 112). The request maybe routed via the network to a POP 120 associated with a routing prefixwithin the network address, where the request may be processed accordingto a content server 122 (e.g., as selected according to load balancingof the POP 120). Specifically, at (7), the POP 120 may load one or moredecoding rules for the network address from the decoding rules datastore 124. In some instances, the loaded rules may be generally static,and the POP 120 may load a current set of decoding rules. In otherinstances, the POP 120 may load a set of rules corresponding to aversion identifier represented by bits of the encoded network address(e.g., where the bits of the encoded network address representing theversion identifier are identifiable without the rules themselves, suchas by locating the bits in a common position across a set of potentialrules).

At (8), the POP 120 can decode DNS-level data from the network address,according to the decoding rules. For example, the POP 120 may utilizethe decoding rules to determine a distribution identifier, hintinformation, and validity information associated with the request.Illustratively, each type of DNS-level data may be obtained myinspecting a set of bits corresponding to the DNS-level data, asidentified in the decoding rules. In some instances, a set of bits maybe further processed according to algorithms of the decoding rules totransform the bits into a format usable by the POP 120 (e.g., byreversing an encoding of a particular type of DNS-level data).

At (9), the POP 120 can validate the request to access content at leastpartly based on validity information included within the network addressto which the request is transmitted. For example, validity informationmay include both a time of generation of a network address and a TTLvalue for the network address (or for a DNS record including the networkaddress). Accordingly, a receiving device may decode the time ofgeneration value and TTL value, and utilize these values to determinewhether the network address should be considered valid (e.g., wherein ifthe time of generation value plus the TTL value does not meet or exceeda current time, the network address may be considered invalid. Asanother example, where the validity information is a digital signaturegenerated based on a cryptographic hash of remaining bits of the networkaddress, the POP 120 may generate a corresponding hash using thoseremaining bits of the network address and a decrypted value representinga decryption of the digital signature using a public key of the DNSservice 112, and verify that the decrypted value and generated hashmatch. In some embodiments, the public/private key pair utilized togenerate a digital signature may be specified within the network address(e.g., by a version identifier identifying a public/private key pairfrom a pre-established list). In other instances, the public/private keypair utilized to generate a digital signature may be separately agreedupon by the DNS service 112 and the POP 120. For example, the DNS server112, the POP 120, or a third component (not shown in FIGS. 3A-3B) mayperiodically generate or select a new public/private key pair for use bythe DNS service 112 and the POP 120, and the POP 120 may, after athreshold period of time subsequent to generation of a newpublic/private key pair (e.g., matching a TTL value of DNS recordsprovided by the DNS service 112), consider network addresses withdigital signatures generated under prior public/private key pairs to beinvalid. This may enable the POP 120 to independently enforce TTL valuesof DNS records using digital signature verification.

In an instance where the decoding rules specify other inputs forvalidity information, such as a region from which the requestoriginates, the POP 120 may verify the digital signature using suchinputs. In the instance that the network address is considered valid,the POP 120 may continue to process the request. Otherwise, the POP 120may consider the request invalid, and decline to further process therequest (e.g., by “blackholing” the request). While validation of arequest is described with reference to the POP 120 generally, suchvalidation may occur at a variety of locations within the POP 120, suchas at a content server 122 or at routers of the POP 120 (which routersare not shown in FIG. 3B) acting as intermediaries between a contentserver 112 and the accessing computing device 102A. In some instances,the public key corresponding to a digital signature may be madepublically available by the content delivery system 110. Thus,components external to the content delivery system 110 may be enabled toverify digital signatures included within network addresses. Forexample, an accessing computing device 102 may include softwareconfigured to validate digital signatures in network addresses returnedas part of a response to a DNS request, which may prevent or deterfalsification or modification of DNS responses (e.g., via aman-in-the-middle attack). As another example, routers or communicationdevices on the network 106 may be configured to verify digitally signednetwork addresses before forwarding such addresses, to prevent malicioustraffic on the network 106.

At (10), in the instance that the network address is considered valid,the POP 120 initiates communication with the accessing computing device102A and obtains content responsive to the request, based at leastpartly on the DNS-level information. Illustratively, the POP 120 mayinitiate secure communications with the accessing computing device 102Abased on a security certificate identified by the hint information ofthe network address. The POP 120 may further access a requested portionof content corresponding to the distribution within the data cache 126based on a distribution identifier of the network address. Thereafter,the POP 120 can return the requested content to the accessing computingdevice 102, at (11). Thus, the accessing computing device 102A canutilize a network address encoded with DNS-level information to accesscontent on the content delivery system 110.

While the interactions of FIG. 3B generally describe interactions thatmay occur with respect to a legitimate accessing computing device 102A,POPs 120 may additionally be configured to process and handle maliciouscommunications from illegitimate accessing computing devices 102.Illustratively, such malicious communications may include invalidvalidity information (e.g., by virtue of the fact that the DNS service112 has altered the validity information since a targeted networkaddress was obtained by the illegitimate accessing computing devices102), and thus may be ignored by the POP 120. Furthermore, becausenetwork addresses may include a distribution identifier as encodedDNS-level data, the POPs 120 may be enabled to identify, from thenetwork address (and potentially without any additional information), adistribution targeted by a network attack. The POPs 120 may thenundertake actions to mitigate the network attack, such as requestingthat the DNS service 112 modify DNS records for the targeteddistribution to include new validity information. Further illustrationsof actions that may be used to mitigate network attacks are described inmore detail within U.S. Pat. No. 9,742,795, entitled “MITIGATING NETWORKATTACKS,” and issued Aug. 22, 2017, the entirety of which is herebyincorporated by reference.

All of the methods and processes described above may be embodied in, andfully automated via, software code modules executed by one or moregeneral purpose computers or processors. The code modules may be storedin any type of non-transitory computer-readable medium or other computerstorage device. Some or all of the methods may alternatively be embodiedin specialized computer hardware.

Conditional language such as, among others, “can,” “could,” “might” or“may,” unless specifically stated otherwise, are otherwise understoodwithin the context as used in general to present that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Disjunctive language such as the phrase “at least one of X, Y or Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to present that an item, term, etc., may beeither X, Y or Z, or any combination thereof (e.g., X, Y and/or Z).Thus, such disjunctive language is not generally intended to, and shouldnot, imply that certain embodiments require at least one of X, at leastone of Y or at least one of Z to each be present.

Unless otherwise explicitly stated, articles such as ‘a’ or ‘an’ shouldgenerally be interpreted to include one or more described items.Accordingly, phrases such as “a device configured to” are intended toinclude one or more recited devices. Such one or more recited devicescan also be collectively configured to carry out the stated recitations.For example, “a processor configured to carry out recitations A, B andC” can include a first processor configured to carry out recitation Aworking in conjunction with a second processor configured to carry outrecitations B and C.

Any routine descriptions, elements or blocks in the flow diagramsdescribed herein and/or depicted in the attached figures should beunderstood as potentially representing modules, segments, or portions ofcode which include one or more executable instructions for implementingspecific logical functions or elements in the routine. Alternateimplementations are included within the scope of the embodimentsdescribed herein in which elements or functions may be deleted, orexecuted out of order from that shown or discussed, includingsubstantially synchronously or in reverse order, depending on thefunctionality involved as would be understood by those skilled in theart.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

What is claimed is:
 1. A content delivery system configured to mitigatenetwork attacks on a domain name, wherein the domain name is associatedwith content provided by the content delivery system, the contentdelivery system comprising: a domain name system (DNS) computing devicecomprising a processor configured with computer-executable instructionsto: obtain one or more encoding rules for encoding DNS-level informationinto network addresses provided by the DNS computing device, wherein theone or more rules comprise multiple rule versions; obtain a request toresolve the domain name into a network address of a host deviceproviding content associated with the domain name; encode, into thenetwork address of the host device and according to the one or moreencoding rules, the domain name and a version identifier associated witha rule version, of the multiple rule versions, utilized in encoding theencoded network address; and return the network address of the hostdevice in response to the request; a computing device comprising aprocessor configured with computer-executable instructions to: obtainone or more decoding rules for decoding DNS-level information encodedinto network addresses by the DNS computing device; detect a maliciousdata packet addressed to the network address of the host device, whereinthe malicious data packet forms at least a part of a network attack onthe content delivery system; decode, according to the one or moredecoding rules, the domain name from the network address of the hostdevice which the malicious data packet is addressed; and identify thedomain name decoded from the network address of the host device to whichthe malicious data packet is addressed as a target of the networkattack.
 2. The content delivery system of claim 1, wherein the networkaddress is formatted as an Internet Protocol version 6 (Ipv6) address.3. The content delivery system of claim 1, wherein the one or moreencoding rules specify information to be included within individual bitsof the network addresses.
 4. The content delivery system of claim 1,wherein the network address comprises a first portion corresponding torouting information on a publically addressable network, and a secondportion including encoded DNS-level information.
 5. The content deliverysystem of claim 1, wherein the computing device is at least one of acontent server computing device or a networking routing computingdevice.
 6. A computer-implemented method for providing DNS-levelinformation within encoded network addresses, the computer-implementedmethod comprising: obtaining one or more rules for encoding DNS-levelinformation into the encoded network addresses and decoding DNS-levelinformation from the encoded network addresses, wherein the rulesspecify a format of the DNS-level information when encoded in theencoded network addresses and individual bits of the encoded networkaddresses to utilize in representing the DNS-level information;receiving a DNS request to resolve a domain name into a network addressof a host device providing content associated with the domain name;using the one or more rules to encode DNS-level information associatedwith the DNS request into the network address of the host device,wherein one or more rules comprise multiple rule versions, and whereinusing the one or more rules to encode the DNS-level informationassociated with the DNS request into the network address of the hostdevice further comprising encoding into the network address a versionidentifier associated with a rule version, of the multiple ruleversions, utilized in encoding the network address; returning thenetwork address of the host device in response to the DNS request;receiving a network packet addressed to the network address of the hostdevice; using the one or more rules to decode the DNS-level informationfrom the network address of the host device; and routing data packetaddress to the network address based at least in part on the DNS-levelinformation decoded from the network address of the host device.
 7. Thecomputer-implemented method of claim 6, wherein the DNS-levelinformation includes at least one of the domain name, securityinformation associated with the domain name, timing information of theDNS request, information specifying a source of the DNS request, orvalidity information indicating a validity of the network addressgenerated based at least in part on the DNS request.
 8. Thecomputer-implemented method of claim 6, wherein the DNS-levelinformation includes the domain name, the computer-implemented methodfurther comprising: identifying the network packet as malicious andforming at least part of a network attack; and identifying the domainname decoded from the network address to which the malicious networkpacket is addressed as a target of the network attack.
 9. Thecomputer-implemented method of claim 6, wherein the DNS-levelinformation includes validity information, and wherein routing the datapacket based at least in part on the DNS-level information decoded fromthe network address comprises: detecting that the validity informationindicates that network packet is addressed to an invalid networkaddress; and discarding the network packet.
 10. The computer-implementedmethod of claim 6, wherein the DNS-level information includes validityinformation, and wherein routing the data packet based at least in parton the DNS-level information decoded from the network address comprises:detecting that the validity information indicates that network packet isaddressed to a valid network address; and routing the network packet toa content server associated with the domain name.
 11. Thecomputer-implemented method of claim 10, wherein the validityinformation indicates a time of the DNS request, and wherein detectingthat the validity information indicates that network packet is addressedto the valid network address includes detecting that a period of timebetween a current time and the time of the DNS request falls with athreshold time-to-live value.
 12. The computer-implemented method ofclaim 10, wherein the validity information includes a digital signatureassociated with a public key, and wherein detecting that the validityinformation indicates that network packet is addressed to the validnetwork address includes verifying the digital signature using thepublic key.
 13. Non-transitory computer-readable media comprisingcomputer-executable instructions for encoding DNS-level informationwithin network addresses that, when executed, cause a computing systemto: obtain one or more rules for encoding the DNS-level information intothe network addresses and decoding the DNS-level information from thenetwork addresses; obtain a request for an encoded network address of ahost device providing content associated with a domain name, wherein therequest includes DNS-level information associated with a DNS request toresolve the domain name into the encoded network address of the hostdevice; encode the DNS-level information into the encoded networkaddress of the host device according to at least the one or more rules,wherein one or more rules comprise multiple rule versions, and whereinthe instructions further cause the computing system to encode into thenetwork address a version identifier associated with a rule version, ofthe multiple rule versions, utilized in encoding the network address;return the encoded network address of the host device in response to therequest; receive a network request associated with the encoded networkaddress of the host device; decode the encoded network address of thehost device according to at least the one or more rules to result in theDNS-level information; and respond to the network request based at leastin part on the DNS-level information obtained by decoding the encodednetwork address of the host device.
 14. The non-transitorycomputer-readable media of claim 13, wherein the network request is atleast one of a request to decode the encoded network address or arequest to obtain content associated with the encoded network address.15. The non-transitory computer-readable media of claim 13, wherein thecomputer-executable instructions cause the computing system to respondto the network request based at least in part on the DNS-levelinformation by at least one of: returning the DNS-level information inresponse to the network request; returning content associated with thenetwork request; discarding the network request; or forwarding thenetwork request to a content server associated with the DNS-levelinformation.
 16. The non-transitory computer-readable media of claim 13,wherein the DNS-level information includes a domain name and anidentifier of a security certificate associated with the domain name,and wherein the computer-executable instructions cause the computingsystem to respond to the network request at least partly by initiating asecure connection utilizing the security certificate.
 17. Thenon-transitory computer-readable media of claim 13, wherein thecomputer-executable instructions cause the computing system to determinethe rule version of the multiple rule versions to utilize in encodingthe encoded network address based at least in part on a current time anda security level associated with the domain name.
 18. The non-transitorycomputer-readable media of claim 13, wherein the DNS-level informationincludes a domain name, and wherein the computer-executable instructionscause the computing system to encode the DNS-level information into theencoded network address at least in part by: hashing the domain nameaccording to a hash function to result in a hash value; and includingthe hash value as a portion of the encoded network address.
 19. Thenon-transitory computer-readable media of claim 18, wherein the hashfunction is a cryptographic hash function.